Much-branched shrub, 0.8–3.5 m; young shoots usually stalked- or setose-glandular. Leaves 4.5–5 × 1.4–2.4 cm, elliptic to obovate, lower surface punctulate, otherwise glabrous; or (rarely) with a few tufts of hairs, even at maturity; petioles with a few setulose glands or more or less glabrous at maturity. Flowers solitary or up to 4, in a lax truss; calyx 1–3 mm; corolla pale yellow, or white flushed rose to pink, with or without purple flecks, funnel-campanulate, nectar pouches lacking, c.30 mm; ovary and style base densely stalked-glandular. Flowering April-May. Royal Horticultural Society (1997)
Distribution China SE Tibet, NW Yunnan
Habitat 3,000–4,250 m
RHS Hardiness Rating H6
Conservation status Vulnerable (VU)
Taxonomic note Closely allied to R. selense but distinguished by its smaller leaves and fewer flowers per truss. In the wild it apparently has a narrower corolla but it is not certain whether this is a consistent diagnostic character. Royal Horticultural Society (1997)
An evergreen shrub 3 to 6 ft high, with slender but stiff young shoots furnished with glands. Leaves clustered at the end of the shoot, oval inclined to oblong, abruptly tapered towards both ends, ending in a very distinct mucro; 3⁄4 to 13⁄4 in. long, half as much wide; more or less glandular when young, eventually glabrous or nearly so, rather glaucous beneath; stalk 1⁄4 in. long, glandular. Flowers two or three together in a terminal cluster each on a glandular stalk up to 11⁄4 in. long. Calyx small, fringed with glands. Corolla widely funnel-shaped, five-lobed, 1 in. long, 2 in. wide, pale rose with a dark blotch at the base, often speckled with crimson, the lobes reflexed. Stamens ten, downy at the base. Ovary and base of style glandular. (s. Thomsonii ss. Selense)
Native of N.W. Yunnan, bordering parts of S.E. Tibet, and of upper Burma; introduced by Forrest in 1914 and also in cultivation from seeds collected by Rock and by Kingdon Ward. It is named after John Martin, who had charge of the rhododendrons at Caerhays Castle, Cornwall. In its best forms, with clear pink flowers heavily freckled with crimson and borne on a low compact bush, this is one of the most charming of rhododendrons, but is rarely met with in gardens. Kingdon Ward’s 6795 from the Seinghku valley, upper Burma, is unusual in having roundish leaves, recalling those of R. thomsonii.
R. eurysiphon – Wrongly placed here. See this supplement under R. stewartianum.